JP2021147522A - Prepreg and fiber-reinforced plastic - Google Patents

Abstract

To provide a fiber-reinforced plastic which is excellent in flame retardancy, and a prepreg which is suitable for manufacturing the fiber-reinforced plastic.SOLUTION: A fiber-reinforced plastic and a prepreg in which base fabric is woven fabric woven by yarns composed of mineral fibers and a resin is a phenol resin, and more than 65 mass% and less than 85% of the mineral fibers are contained.SELECTED DRAWING: Figure 1

Description

The present invention relates to prepregs and fiber reinforced plastics.

Conventionally, fiber reinforced plastic (FRP) has been widely used as a member for a body of a freight vehicle, a pleasure boat, and the like.
Most of the fiber reinforced plastics are generally molded by placing a glass mat in a mold and then injecting a thermosetting resin into the mold, but the thermosetting resin such as an unsaturated polyester resin is in an uncured state. There is also a method of manufacturing using a material called prepreg impregnated in a base cloth such as a glass mat.
In the manufacturing method using prepregs, the fiber reinforced plastic is produced by stacking a plurality of such prepregs as required and then heat-pressing them.

In conventional fiber reinforced plastics, the base cloth is carbon fiber and the thermosetting resin is epoxy resin, and other than the combination of glass mat and unsaturated polyester resin is widely known (). See Patent Document 1 below).
In recent fiber reinforced plastics, thermoplastic resins are sometimes used as the resins to be supported on the base fabric.

Fiber reinforced plastics with a thermoplastic resin supported on the base cloth are excellent in moldability because they are easily deformed by heating, but the heat resistance of the product is that those using thermosetting resin. Is excellent.

JP-A-2019-89931

As shown in Patent Document 1 above, it has been studied to impart not only heat resistance but also flame retardancy to fiber reinforced plastics.
Generally, the flame retardancy of plastics is about self-extinguishing after ignition, but if the flame retardancy is improved to the extent that it exhibits fire resistance and flame resistance, only non-combustible materials such as metals can be used so far. The scope of application of fiber reinforced plastics can be expanded to areas where they did not exist.
However, fiber reinforced plastics having excellent flame retardancy and prepregs suitable for producing such fiber reinforced plastics have not been provided so far.
Therefore, an object of the present invention is to provide a fiber reinforced plastic and a prepreg that exhibit higher flame retardancy than conventional ones.

In order to solve the above problems, the present invention
A fiber reinforced plastic comprising one or more base fabrics and a resin supported on the base fabrics.
A woven fabric in which at least one of the base fabrics is woven with threads composed of mineral fibers.
The resin is a phenol resin,
Provided is a fiber reinforced plastic, which contains the mineral fibers in a proportion of more than 65% by mass and less than 85% by mass.

In order to solve the above problems, the present invention
A prepreg comprising a base cloth and an uncured resin supported on the base cloth.
Provided is a prepreg in which the base fabric is a woven fabric woven with threads composed of mineral fibers, the resin is a phenol resin, and the mineral fibers are contained in a proportion of more than 65% by mass and less than 85% by mass. do.

According to the present invention, a fiber reinforced plastic having excellent flame retardancy and a prepreg suitable for producing such a fiber reinforced plastic can be provided.

The schematic perspective view which shows the prepreg of one Embodiment. The schematic plan view which shows the state of the base cloth of a prepreg. The schematic perspective view which shows the state of the base cloth of a prepreg (enlarged view of part X of FIG. 1). The schematic perspective view which shows the fiber reinforced plastic of one Embodiment.

An embodiment of the present invention will be described with reference to the drawings.
First, the prepreg will be described.
The prepreg 1 of the present embodiment includes a base cloth 10 made of a fiber woven fabric and an uncured resin (not shown) supported in a state of being impregnated in the base cloth 10.
The base cloth 10 in the present embodiment is a woven fabric woven with threads composed of mineral fibers.
In the prepreg 1 of the present embodiment, the resin is a phenol resin, and the mineral fibers are contained in a proportion of more than 65% by mass and less than 85% by mass.

The prepreg 1 of the present embodiment is used as a material for forming the fiber reinforced plastic 100 having excellent flame retardancy, as will be described later.
Among them, it is used as a material for forming a fiber reinforced plastic 100 which is not only excellent in flame retardancy but also excellent in flame resistance so that when a flame is exposed from one side, the flame does not escape to the other side.
More specifically, the prepreg 1 of the present embodiment is used as a material for forming the fiber reinforced plastic 100, which does not allow the flame to penetrate when a flame of 800 ° C. is applied from one side for 10 minutes.

In the prepreg 1 of the present embodiment, the base cloth 10 is a mineral fiber woven fabric as described above in order to make the fiber reinforced plastic 100 exhibit the excellent flame retardancy as described above.
The base cloth 10 of the present embodiment includes a plurality of warp threads 11 arranged so as to be parallel to each other, and a plurality of weft threads 12 extending in a direction orthogonal to the warp threads and arranged so as to be parallel to each other. There is.
The base cloth 10 of the present embodiment may be a plain woven fabric, a twill woven fabric, or a red woven fabric.
In plain woven fabrics, it is difficult for gaps to be formed between adjacent warp threads or between adjacent weft threads when tensile stress or the like is applied.
Therefore, it is advantageous to adopt the plain woven fabric for the base cloth 10 in that it becomes easy to obtain the fiber reinforced plastic 100 which is difficult for the flame to penetrate at the time of contact with the flame.
On the other hand, twill woven fabrics and red woven fabrics are superior in suppleness to plain woven fabrics when compared with the same fineness and number of threads of warp and weft.
Therefore, adopting a twill woven fabric or a red woven fabric for the base cloth 10 is advantageous in improving the moldability when producing the fiber reinforced plastic 100.
The base fabric 10 preferably has a fine texture to some extent, and the weaving density (the number of threads driven per inch) between the warp threads 11 and the weft threads 12 is preferably a certain value or more.
The weaving densities of the warp 11 and the weft 12 are preferably 9 yarns / inch or more, more preferably 10 yarns / inch or more, and further preferably 11 yarns / inch or more.
The weaving densities of the warp 11 and the weft 12 may be 12 threads / inch or more, or 13 threads / inch or more.
The weaving densities of the warp 11 and the weft 12 are preferably 90 yarns / inch or less, more preferably 80 yarns / inch or less, and further preferably 70 yarns / inch or less.
The weaving densities of the warp 11 and the weft 12 may be 60 yarns / inch or less, or 50 yarns / inch or less.
The warp threads 11 and the weft threads 12 may have the same or different weaving densities.

The warp yarn 11 and the weft yarn 12 of the present embodiment may be spun yarn or filament yarn.
When the warp 11 and the weft 12 of the present embodiment are the filament yarns, these yarns may be monofilament yarns or multifilament yarns.
When the warp 11 and the weft 12 of the present embodiment are multifilament yarns, these yarns are twisted yarns (twisted yarns) even if they are rovings (plyed yarns) in which the filaments are simply aligned. There may be.

When the warp 11 and the weft 12 of the present embodiment are twisted yarns, these yarns have a number of twists of 500 times / m or more and less than 1000 times / m even if the number of twists is less than 500 times / m. It may be medium-twisted yarn.
These yarns may be strong twisted yarns having a number of reliance of 1000 times / m or more and less than 2500 times / m, or super strong twisted yarns having a number of reliance of 2500 times / m or more.

In the base fabric 10 of the present embodiment, at least one of the warp 11 and the weft 12 is preferably a multifilament yarn, and more preferably both are multifilament yarns.
In the base fabric 10 of the present embodiment, both the warp yarn 11 and the weft yarn 12 are multifilament yarns.

Normally, there are threads in the gaps formed between the two adjacent warp threads 11 and the gaps formed between the two adjacent weft threads 12 because only the resin is present. There is a possibility that the flame will pass through more easily when contacting the flame than in the place where it is.
In the woven fabric, as shown in FIG. 3, one of the two adjacent weft threads 12 (12a) passes under the warp thread 11, and the other weft thread 12 (12b) passes over the upper side of the warp thread 11. At the passing portion, a gap V is likely to be formed next to the warp thread 11 according to the thickness of the warp thread 11.
That is, at a position where two adjacent weft threads 12 sandwich the warp threads 11 from above and below, as shown in the figure, the side edge portion of the warp threads 11, the upper edge portion of the lower weft threads 12a, and the upper side. A triangular gap V surrounded by the lower edge of the weft 12b can be formed.
A gap V may be formed on the side of the weft 12 as well.
That is, even in a place where one of the two adjacent warp threads 11 passes under the weft thread 12 and the other warp thread 11 passes above the weft thread 12, the thickness of the weft thread 12 is next to the weft thread 12. A triangular gap V can be formed accordingly.

When the base cloth 10 is made of a plain weave woven cloth, the warp threads 11 and the weft threads 12 appear alternately in the vertical direction and the horizontal direction, respectively, and the gap V can be formed in many places. In the case of a red woven fabric or a twill woven fabric, the number of places where such a gap V can be formed is smaller than that of a plain woven fabric.

Compared to the base cloth 10 woven with monofilament yarn, the warp yarn 11 and the weft yarn 12 are composed of the multifilament yarn, so that the warp yarn 11 and the weft yarn 12 are easily deformed into a flat shape, and the gap between them is large. The area of V can be small.
Even if the warp 11 and the weft 12 are multifilament yarns, if the multifilament yarn is a strong twist yarn or a super strong twist yarn, it is difficult to form a flat shape, and it is difficult to reduce the area of the gap V.
From such a viewpoint, the warp 11 and the weft 12 in the present embodiment are preferably roving, and even if they are twisted, the sweet twisted yarn is preferably a medium twisted yarn.

The warp threads 11 and the weft threads 12 may have the same or different filament thickness and number of filaments.
The fineness of the filaments constituting the warp 11 and the weft 12 is, for example, preferably 0.5 dtex or more, more preferably 1 dtex or more, and further preferably 1.5 dtex or more.
The fineness of the filaments constituting the warp 11 and the weft 12 is preferably 10 dtex or less, more preferably 8 dtex or less, and further preferably 6 dtex or less.
The density of the minerals constituting the mineral fibers is usually 2.0 g / cm ^{3 to} 3.0 ^{g / cm 3} , and the thickness (diameter) of the filament is usually 5 μm or more and 25 μm or less.
The thickness of the filament can be calculated as the diameter of a circle having the same area as the cross-sectional area by obtaining the cross-sectional area of the filament.

The warp yarn 11 and the weft yarn 12 preferably have 200 or more filaments constituting one yarn.
The number of the filaments is more preferably 250 or more, and further preferably 300 or more.
The number of the filaments may be 400 or more, or 500 or more.
The number of the filaments is preferably 2000 or less, and more preferably 1800 or less.
The number of the filaments may be 1600 or less, 1400 or less, or 1200 or less.

The fineness (total fineness) of the warp 11 and the weft 12 is preferably 500 dtex or more, more preferably 550 dtex or more, and further preferably 600 dtex or more.
The fineness of each of the warp 11 and the weft 12 may be 700 dtex or more, or 800 dtex or more.
The fineness of each of the warp 11 and the weft 12 is preferably 5000 dtex or less, more preferably 4500 dtex or less, and further preferably 4000 dtex or less.
The fineness of each of the warp 11 and the weft 12 may be 3500 dtex or less, or 3000 dtex or less.
The warp 11 and the weft 12 may have the same or different fineness.

The base cloth 10 preferably has a cover factor of 1000 or more.
The cover factor of the base cloth 10 is more preferably 1100 or more, further preferably 1200 or more, and particularly preferably 1300 or more.
The cover factor of the base cloth 10 may be 1400 or more, or 1500 or more.
The cover factor of the base cloth 10 is preferably 3500 or less, more preferably 3300 or less, and particularly preferably 3100 or less.
The cover factor of the base cloth 10 may be 3000 or less, or 2900 or less.

The cover factor of the base cloth 10 is calculated by the following formula.

CF = Nw · (Dw ^1/2 ) + Nf · (Df ^1/2 )

CF: Cover factor Nw: Weaving density of warp threads (book / inch)
Dw: Warp fineness (dtex)
Nf: Weft weaving density (book / inch)
Df: Weft fineness (dtex)

The base cloth 10 of the present embodiment preferably has a mass (weight) per unit area of 100 g / m ² or more.
The basis weight is ^{more preferably 120 g / m 2} or more, and further preferably 150 g / m ² or more.
The basis weight is ^{preferably 600 g / m 2} or less, and ^{more preferably 500 g / m 2} or less.

Examples of the mineral fibers constituting the warp 11 and the weft 12 include rock wool and basalt fiber.
Among them, basalt fiber is preferable as the mineral fiber.
Since the warp threads 11 and the weft threads 12 are composed of continuous fibers of basalt fibers, they exhibit high tensile strength, and it is difficult for gaps to be formed even when tensile stress or the like is applied to the base cloth 10.

The resin to be supported on the base cloth 10 is preferably a phenol resin having excellent flame retardancy among thermosetting resins.
The prepreg 1 of the present embodiment is provided with an uncured phenol resin impregnated in the base cloth 10.
The phenol resin may be a resol type or a novolak type.
The resol type phenol resin has a structure in which one of the hydrogens of the phenyl group contained in the repeating unit is substituted with a methoxy group, and retains a large number of hydroxyl groups even after curing.
Therefore, the resole-type phenol resin is likely to form a crosslinked structure by a dehydration condensation reaction during combustion, which is advantageous for the formation of char and can be expected to have the effect of generating water vapor and reducing combustibility by diluting the flammable gas. ..

The phenol resin is preferably a water-soluble phenol resin.
Since the phenol resin is water-soluble, the base cloth 10 can be impregnated in the state of an aqueous solution or a water emulsion, and the possibility that a residual solvent is generated in the prepreg 1 and the fiber reinforced plastic 100 can be suppressed.
The prepreg 1 preferably contains an organic solvent such as alcohols and ketones in an amount of 2% by mass or less in order to form the fiber reinforced plastic 100 having high flame retardancy.
The content of the organic solvent in prepreg 1 is more preferably 1% by mass or less, and further preferably 0.5% by mass or less.
It is particularly preferable that the content of the organic solvent is substantially 0% by mass or less.
The content of the organic solvent can be measured by GC-MS or the like.

In the present embodiment, it is preferable to stack and use a plurality of prepregs 1 when forming the fiber reinforced plastic 100.
Therefore, the phenol resin preferably has good fluidity and is preferably liquid at room temperature (23 ° C.) so that voids and the like are less likely to occur during lamination.

The content of the phenol resin in prepreg 1 is, for example, 15% by mass or more and 35% by mass or less.
The prepreg 1 may contain various additives and the like in addition to the phenol resin.
However, in order to make the fiber reinforced plastic 100 exhibit excellent flame retardancy, it is preferable that the fiber reinforced plastic 100 contains the mineral fibers in a proportion of more than 65% by mass.
Therefore, the content of the mineral fiber in prepreg 1 is preferably more than 65% by mass, more preferably more than 70% by mass.
The content of the mineral fiber in the fiber reinforced plastic 100 or the prepreg 1 may be 71% by mass or more, or 72% by mass or more.
The content of the mineral fibers in the fiber reinforced plastic 100 and the prepreg 1 is usually less than 85% by mass.
The content of the mineral fiber in the fiber reinforced plastic 100 or the prepreg 1 may be 83% by mass or less, 81% by mass or less, or 79% by mass or less.

Examples of the additive contained in the prepreg 1 include a catalyst and a curing agent that contribute to the curing reaction of the phenol resin.
In addition, examples of the additive include an ultraviolet absorber, a light stabilizer, a weather resistant agent, an antioxidant, an antistatic agent, a coloring agent, an antibacterial agent, an antibacterial agent, an insect repellent and the like.

A flame retardant may be added to the prepreg 1 as the additive.
When the flame retardant is contained in the prepreg 1, it is preferable to select a flame retardant that does not generate a harmful gas when the fiber reinforced plastic 100 is burned.
The flame retardants include aluminum hydroxide and magnesium hydroxide rather than phosphorus-based flame retardants such as red phosphorus and ammon polyphosphate, and halogen-based flame retardants such as bromine-based flame retardants and chlorine-based flame retardants. It is preferable to use metal hydroxides such as, metal carbonates such as calcium carbonate, expanded graphite and the like.

The total content of the halogen-based flame retardant in prepreg 1 of the additive is usually 5% by mass or less, and the total content of metal hydroxide, metal carbonate, or expanded graphite is usually 20% by mass or less. It is said that.

The prepreg 1 of the present embodiment preferably has a mass (weight) per unit area of 120 g / m ² or more.
The basis weight is ^{more preferably 150 g / m 2} or more, and further preferably 180 g / m ² or more.
The basis weight is ^{preferably 650 g / m 2} or less, and ^{more preferably 600 g / m 2} or less.

The fiber-reinforced plastic 100 of the present embodiment is formed by heating the prepreg 1 to a temperature (curing start temperature) or higher at which a curing reaction occurs in the phenol resin.
The fiber reinforced plastic 100 is preferably produced by heating the prepreg 1 while pressurizing it in the thickness direction.
As a result, the excess phenol resin is eliminated, and the fiber reinforced plastic 100 having a mineral fiber content higher than that of prepreg 1 can be obtained.

The fiber reinforced plastic 100 of the present embodiment illustrated in the figure is made by laminating and integrating a plurality of prepregs 1, and has a multilayer structure according to the number of prepregs 1 used.
The fiber-reinforced plastic 100 of the present embodiment is a press-molded product in which four prepregs 1 are hot-pressed and laminated and integrated, and the first layer 100a and the second layer 100b are sequentially formed from one surface side to the other surface side. , A multi-layer structure having a layer structure of a third layer 100c and a fourth layer 100d.

Each of the first layer 100a, the second layer 100b, the third layer 100c, and the fourth layer 100d is composed of a cured product obtained by thermosetting the prepreg 1.
The prepreg 1 constituting each layer from the first layer 100a to the fourth layer 100d may have the same or different types and content ratios of the base cloth 10 and the phenol resin.
For example, in the fiber reinforced plastic 100 of the present embodiment, the base cloth 10 in the first layer 100a may be a twill woven fabric, and the base cloth 10 from the second layer 100b to the fourth layer 100d may be a plain woven fabric.
Even when a plurality of prepregs 1 are laminated, since at least one of the base fabrics 10 is a twill woven fabric or a red woven fabric, the fiber reinforced plastic 100 can be easily formed as compared with the case where all the base fabrics are plain woven fabrics.

The thicker the fiber reinforced plastic 100, the higher the flame retardancy.
The fiber reinforced plastic 100 preferably has an average thickness of 0.5 mm or more.
The average thickness of the fiber reinforced plastic 100 is more preferably 0.7 mm or more, and further preferably 0.9 mm or more.
The average thickness of the fiber reinforced plastic 100 is preferably 10 mm or less in consideration of lightness.
The average thickness of the fiber reinforced plastic 100 is more preferably 8 mm or less, and further preferably 6 mm or less.
The average thickness of the fiber reinforced plastic 100 can be obtained, for example, by dividing its volume by the area of the outer surface.
For the fiber reinforced plastic 100, for example, the area ratio (the ratio to the area of the entire outer surface) occupied by the region having a thickness of 1 mm or less is preferably 30% or less, and more preferably 20% or less.

By having a laminated structure in which a plurality of the base fabrics 10 are laminated by using a plurality of prepregs 1, even if a local gap between threads is formed in one base cloth 10, the threads of the other base cloth can be used. The gap can be closed.
That is, even if the fiber reinforced plastics have the same thickness, if only one thick base cloth is provided, if a gap is formed in the base cloth, the gap will penetrate the fiber reinforced plastic 100 over the entire thickness direction. However, such a situation can be prevented by the fiber reinforced plastic 100 of the present embodiment in which a plurality of base fabrics 10 are laminated.

The fiber-reinforced plastic 100 of the present embodiment is arranged so that the warp threads 11 and the weft threads 12 of two adjacent base fabrics 10 adjacent to each other in the stacking direction intersect at an angle of more than 0 ° and less than 90 °. Is preferable.
The angle formed by the warp threads 11 and the weft threads 12 of the two adjacent base fabrics 10 in the vertical direction is preferably 10 ° or more and 80 ° or less, and more preferably 20 ° or more and 70 ° or less. It is more preferably 30 ° or more and 60 ° or less.

In the present embodiment, the flat plate-shaped fiber reinforced plastic 100 is illustrated, but the fiber reinforced plastic 100 may have a three-dimensional shape, and the shape is not particularly limited.
Further, the fiber reinforced plastic 100 of the present embodiment can be used as various members by further laminating a surface sheet or coating the surface.

The fiber reinforced plastic 100 of the present embodiment is, for example, a housing or substrate material of an electric / electronic device; a building member such as a piping material, a wall material, a roofing material; a bicycle, a motorcycle, an automobile, a railroad vehicle, a ship, an aircraft, and the like. It can be used as a member for constituting the body or internal parts of a moving body such as a rocket;
The fiber reinforced plastic 100 of the present embodiment can be used as, for example, an automobile body part such as a bumper, a front grill, a fender, and a side molding.
The fiber reinforced plastic 100 of the present embodiment can also be used, for example, as an interior material for an automobile, a battery case (collector), a member arranged in an engine room such as a battery cover (closure), and the like.

The specific embodiments and uses of the prepreg and the fiber reinforced plastic of the present embodiment are not limited to the above, and the present invention is not limited to the above specific examples.

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.

(Example 1)
A coating liquid in which a resole-type phenol resin was dispersed in an aqueous solvent was prepared.
A coating liquid is applied to a square basalt fiber brocade fabric (grain 380 g / m ² ) having a size of 1 m ² , and the coating liquid is dried to support 146 g of phenol resin, and contains 72% by mass of basalt fiber. The prepared prepreg was prepared.
Four layers of the prepreg were laminated and set in a box-shaped mold, and pressed with a press machine (150 ° C.) to form a box-shaped fiber reinforced plastic.
The obtained fiber reinforced plastic had an overall thickness of 1 mm and had a good appearance.
In order to evaluate the flame retardancy of this box-shaped fiber reinforced plastic, the bottom portion of the fiber reinforced plastic was heated from below with a flame at 800 ° C. for 10 minutes.
As a result, it was confirmed that the flame did not penetrate even after 10 minutes had passed, and it was confirmed that the fiber reinforced plastic had excellent flame retardancy.

(Example 2)
A prepreg and a fiber-reinforced plastic were produced in the same manner as in Example 1 except that the base cloth of the prepreg was changed from a red woven fabric to a twill woven fabric, and the flame retardancy was evaluated in the same manner as in Example 1.

(Example 3)
The prepreg and the fiber reinforced plastic were produced in the same manner as in Example 1 except that the base cloth of the prepreg was changed from the red woven fabric to the twill woven fabric and eight layers of the prepreg were laminated to produce a fiber reinforced plastic having a thickness of 2 mm. The flame retardancy was evaluated in the same manner as above.

(Example 4)
A prepreg and a fiber-reinforced plastic were produced in the same manner as in Example 1 except that the base cloth of the prepreg was changed from a red woven fabric to a plain woven fabric, and the flame retardancy was evaluated in the same manner as in Example 1.
It was confirmed that the moldability of the prepreg obtained at this time was slightly inferior to that of Examples 1 to 3.

(Comparative Example 1)
Example 1 except that the base cloth of the prepreg was changed from the red woven fabric to the twill woven fabric and the solvent of the coating liquid was changed to methanol instead of water to prepare a prepreg having a basalt fiber content of 65% by mass and a fiber reinforced plastic. A prepreg and a fiber reinforced plastic were prepared in the same manner as in Example 1, and the flame retardancy was evaluated in the same manner as in Example 1.
The fiber-reinforced plastic obtained at this time was heated for 10 minutes, and the flame applied from below penetrated upward.

(Comparative Example 2)
The prepreg and fiber reinforced plastic were prepared in the same manner as in Comparative Example 1 except that the solvent of the coating liquid was returned to water to prepare a prepreg and fiber reinforced plastic having a basalt fiber content of 60% by mass, and the same as in Comparative Example 1. The flame retardancy was evaluated.
The fiber-reinforced plastic obtained at this time was heated for 10 minutes in the same manner as in Comparative Example 1, and the flame applied from below penetrated upward.
The above results are shown in the table below.

From the above results, it can be seen that according to the present invention, a fiber reinforced plastic having excellent flame retardancy and a prepreg suitable for producing such a fiber reinforced plastic are provided.

1: Prepreg, 11: Warp, 12: Weft, 100: Fiber reinforced plastic

Claims (9)

A fiber reinforced plastic comprising one or more base fabrics and a resin supported on the base fabrics.
A woven fabric in which at least one of the base fabrics is woven with threads composed of mineral fibers.
The resin is a phenol resin,
A fiber reinforced plastic containing the mineral fibers in a proportion of more than 65% by mass and less than 85% by mass. The fiber-reinforced plastic according to claim 1, wherein the phenol resin is a resol type phenol resin. The fiber-reinforced plastic according to claim 1 or 2, wherein the mineral fiber is a basalt fiber. The fiber-reinforced plastic according to any one of claims 1 to 3, wherein at least one of the base fabrics is a twill woven fabric or a red woven fabric. The fiber-reinforced plastic according to any one of claims 1 to 4, wherein a plurality of the base fabrics are laminated. A prepreg comprising a base cloth and an uncured resin supported on the base cloth.
A woven fabric in which the base fabric is woven with threads composed of mineral fibers.
The resin is a phenol resin,
A prepreg containing the mineral fiber in a proportion of more than 65% by mass and less than 85% by mass. The prepreg according to claim 6, wherein the phenol resin is a water-soluble phenol resin. The prepreg according to claim 6 or 7, wherein the mineral fiber is a basalt fiber. The prepreg according to any one of claims 6 to 8, wherein the base cloth is a twill woven fabric or a red woven fabric.

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